It is known to use certain methods for building concrete floor slabs on the above grade floors of multi-story buildings. One method simply builds forms in place, pours the floor slab, and removes the forms after the slab reaches sufficient strength. Pans are used to form voids in the floor slab to reduce weight, while maintaining strength. This method allows the floor system to be inherently fireproof, to create thin floor sections, and to be reusable. This method, however, is costly, requires long construction times, and provides for a floor system having a heavy selfweight.
Another method involves creating a structural system with steel beams or open web joists, attaching corrugated metal decking to provide a form and casting the floor on the decking. The decking and the structural supports remain in place. This method allows for low selfweight, relatively fast construction, and relatively low cost. This method, however, requires the steel beams or joists to be fireproofed, the overall floor system to be relatively deep (often causing the building to be taller), and mechanical systems that usually run below the floor joists (which further increases building height).
Another method involves making a precast concrete element having a portion of the floor slab in its construction, placing the element(s) on structural supports and casting a thin topping slab over the slab portion for the final finished floor. The precast elements include single tees, double tees, hollow-core slabs, and flat slabs. The resulting floor system is fireproof, has a relatively fast construction time, and allows for offsite fabrication of large floor components. This method, however, is costly, expensive to transport, and, in the case of tees, results in a relatively deep floor system.